Plate 21 



The level of transformation of granular trichohyalin into the fibrous 

 form as seen in Henle's layer of the human-hair follicle. On the l.h.s. (A) 

 is a light micrograph in which may be seen the edge of the hair cortex C 

 containing fibrils of keratin and pigment granules, the hair cuticle Cu, 

 the cuticle of the inner root sheath, Huxley's layer containing granular 

 trichohyalin H and Henle's layer He in which the sudden change from the 

 granular section G into the hyaline birefringent, coherent section B is 

 evident. An electron micrograph of the portion encircled (in an adjacent 

 section) is shown on the r.h.s. (B) where the fibrous strings, /, of trans- 

 formed keratohyalin may be seen extending from the tips of the elongated 

 granules G. Dense particles persist in the cytoplasm. PTA stain. Taken 

 from Birbeck and Mercer (1957). 



